Can a yeast infection or hemorrhoids cause lower back pain? my back pain has increased a lot and i currently have both these conditions.

No: Generally speaking a Yeast infection and/or a hemorrhoid would not cause back pain.

Not really: hemorrhoid can cause anal/rectal pain- not related to a yeast infection.

Lets review your que: No the cause is most likely something else . Yeast infection of the penis usually causes discharge and itching maybe redness. If you were chronically ill and need to self-cath or have a permanent catheter in you could get a yeast infection into the bladder which could cause back pain. Hemmorrhoids should only cause pain in the rectal area. Most likely it is muscular in nature

Pain: Interesting question. I will say yes. Particularly true of anal pain because there are reflexes which cause 'referred pain' to other areas. Anal pain causes other muscles in the region to tighten. Vaginal candida, unless severe, is less likely to be the culprit.